Production of metal tubing and of tubular metal articles or instruments



Jan. 5 1926. r 1,568,369

S. J. EVERETT PRODUCTION OF METAL TUBING AND OF TUBULAR METAL ARTICLES 0R INSTRUMENTS Filad Oct. 20, 1923 Patented Jan. 5, 1926.

PATENT OFFICE.

UNITED STATES SAMUEL JAMES EVERETT, OF THORNTON HEATH, ENGLAND.

PRODUCTION OI METAL TUBING AND 01 TUBULAR METAL ARTICLES OR INSTRU- MENTS. I

Application filed October 20, 1923. Serial No. 689,786.

To all whom it may concern:

Be it known that I, SAMUEL JAMns Evmmrrr, a subject of the King of Great Britain, residing at No. 324-London Road, Thornton Heath, in the county of Surrey, England, have invented certain new and useful Improvements in and Connected With the Production of Metal Tubing and of Tubular Metal Articles or Instruments, of

which the following is a specification.

This invention comprises improvements in and connected with the production of metal tubing and of tubular metal articles or in-- struments. The invention is primarily concerned with the manufacture of tubes ofhard or tough metal, such as steel, nichrome and the like, the principal object being to enable tubes of relatively small diameter or gauge to beproduced on mandrils or cores which are readily removable from such tubes in spite of the smallness of the bore of the latter. The invention has for a further object to produce in this manner lined tubes of very small diameter, such tubesbeing advantageous for the manufacture (if hypo-i dermic syringe needles.

According to this invention, the tubes are A I produced by rolling, swaging or drawing a and decreasin in diameter and freeing the tube length. nthe msging of tubes of very small gauge, such'as are required for by 0- dermic syringe needles, 9. length of tube with its contained mandril or core is severed, this length being about equal to two needle lengths. The tube length is then divided by severin or breaking one half length from the ot er without cutting or breaking the mandril or core and the two half len he are pulled apart, the stretching and re action in diameter of the mandril dueto such pullingenabling the separation of the half lengths, or'needle lengt s, or ,core to be readily effected. Lined tubes may be produced by interposing a tube of lining metal, such as silver, or nickel-silver, between the billet and m'andril.

from'the mandril This manufacture of tubing is very advantageously adopted in the manufacture of hypodermic needles articularly when these are to be made of t e so-called rustless or stainless chrome or like steel. Owing to the smallness of the gauge, it is not practical to impart to the cylindrical Wall of the bore the high polish which is imparted to the ex terior of the tube'or needle and which is necessary for maintenance of the rustless or stainless character of the metal. For this reason, a lining of silver or nickel silver, or like non-corrodible metal is provided in the manner described.

In order to enable the invention to be readily understood,.reference will be made to the accompanying drawing, in the course of a description of one suitable method of carrying out the invertion. In the drawing Figure 1 is'a. longitudinal sect-ion of a ,core'immediately surrounded by a tube of lining metal which, in turn, is surrounded by a tubular billet of steel or the like.

Figure 2 is an enlarged longitudinal section of a finished tube with its core shown in elevation, the breaking of a length of this tube prior to removal from the core being indicated by broken lines.

Figure 3 is an enlarged perspective view of a hypodermic syringe needle made from a length of tubing such as is seen in Figure 2.

Assuming that stainless steel hypodermic needles are to be manufactured, a mandril or core or of brass or nickel silver, of suitable. length and diameter, is coated with graphite b or the like, and a length (1 of silver, nickel silver, or other incorrodible lining metal is passed on to-the mandril or core a. The exterior of the tube length 0 is coated at d with borax or like fiux and it may also be coated with a solder. The mandril or core av with its enclosing tube of lining metal bis nowinserted into the bore of the tubular billet e of stainless or chrome steel and this composite object is subjected to rolling,;swaging or drawing for the production of a tube of the desired gauge, as for example the, tubular needle f tor a hypodermic syringe, such as is seen in Figure 3.

The tube is subjected to heat treatment A to be welded, soldered or intimately allied with the interior of the steel tube, whereby such interior is protected and will not corrode, although not of a polished nature. In Figure 2, the lining of the tube after the rolling, swaging or drawing and heating, is seen to be merged into the outer steel and is indicated by dotted lines.

A length of tubing with its contained core equal to about two needle lengths is now out off. This length of tube is severed in the middle, or isnbroken at that point by ju; dicious bending as illustrated at g in Figure 2, but without cuttin or breaking the core a, and the two halfengths, or two needle lengths, (one needle length being indicated in chain lines at h in Figure 2) are pulled apart. The elongation and reduction in diameter of" the core a due to the pulling, enables a clean separation of the interior of the needle lengths from the core to be' effected. V i

Alternatively, the main length, such as the length'to the left hand side of the break 9 in Figure 2, may be suitably held and a desired length, such as the needle length h of the tube only is severed or' broken and pulled cit, as will now be readily understood.

I claim 1. The production of a lined steel tube of small gauge consisting in the reduction to small gauge of a composite billet comprising an outer steel tube, an inner tube of non corrodible metal, a core of metal capable of extreme elongation and retention of tensile strength, and a uniting medium between said outer and inner tubes, subjecting said tubes and core to a heat treatment, severing a length of the finished tube but not the core and removing said length of tube from the core by a pulling operation which extends said core, substantially as set forth.

2. The production of hard metal tube lengths consisting in the reduction to small gauge of a tubular billet containing a pare ot metal capable of extreme elongation and retention of tensile strength, severing a length of the finished tube but not the core,

and removing said length by a pulling operation which extends said core substantially as set forth. n

3. The production of tubular steel instruments consisting in the reduction small gauge of a COPQPOSltB blllGt composed of an outer steel tube, an inner tube of non-corrodible metal and acore of metal capable of extreme elongation and retention of tensile strength, subjecting the said tubes and core to a heat treatment, severing a length of the finished tube but not the core, and removing said length by a pulling operation which extends said core substantially as set forth.

4.7The of production a hypodermic syringe needle from a composite billet comprising an outer tube of stainless steel, an inner lining tube of non-corrodible non-ferrous metal, and a core of metal capable of extreme elongation and retention of tensile strength, consisting in the reduction to small gauge of said composite billet, subjecting said tubes and core to heat treatment for uniting said outer tube'and said lining tube, severing a needle length of said tube without severing said core, and removing said length by a pulling operation which extends said core substantially as set forth.

5. The production of hypodermic syringe needles from a composite billet comprising an outer tube of stainless steel, an inner lining tube of non-corrodible non-ferrous metal and a Core of metal capable of extreme elongation, and retention of tensile strength, consisting in the reduction to small gauge of said composite billet, subjecting said tubes and core to heat treatment for uniting said outer tube and said lining tube, severing from the small gauge tubing and core a portion equal to two needle lengths, effecting a breakage in the tubing of said portion between its ends without breaking the contained core, and effecting removal of the tube portions from the core by pulling themapart and extending said core substantially as set forth.

SAMUEL JAMES EVERETT. 

